Safety stop mechanism for knitting machines



Oct. 30, 1951 R HARZER 2,573,261

SAFETY STOP MECHANiSM FOR KNITTING MACHINES Filed Aug. 5, 1950 2 SHEETS-SHEET l INVENTOR: Eugene flz/aalffiarzci;

A TTORNEYS.

Oct. 30, 1951 E. R. HARZER 2,573,261

SAFETY STOP MECHANISM FOR KNITTING MACHINES Filed Aug. 5, 1950 2 SHEETS-SHEET 2 INVENTOR: Eu ene fiuaalffiarzei;

BY @Mw A TTORNEYS.

Patented Oct. 30, 1951 SAFETY STOP MECHANISM FOR KNITTING MACHINES Eugene Rudolf Harzer, Elizabethtown, Pa., as-

signor to Karl Lieberknecht, 1110., Reading, Pa., a corporation of Pennsylvania Application August 5, 1950, Serial No. 177,845 2 Claims. (01. 66157) This invention relates'to safety stop mechanism for knitting machines, particularly straight knitting machines of the multi-section Cotton type extensively used in the commercial production of fullfashioned hosiery and the like. In machines of the latter type, the slur cams for actuating the sinkers and the yarn carriers derive their movements respectively from horizontally-arranged slur drive and friction box bars which are reciprocated 'endwise in synchronism during the knitting, so that the yarn carriers will always be ahead of slur cocks in the direction of traverse. Thus if the two bars become un- 2 9 in Fig. 1. In the illustrated instance, the slur box-connecting and the friction bars "I and 6 are reciprocated endwise from separate couliering mechanisms l and I l whereof the oscillated arms 12 and I3 are connected to cross heads l4 and H: which slide on a fixed horizontal guide rod I6,

timed, i. e., are differentially moved, as sometimes occurs as a consequence of maloperation or failure of the means by which they are reciprocated, smashes result through fouling of the sinkers by the yarn carriers. contingencies is expensive, not only from the standpoint of the broken or damaged parts which must be replaced and of the labor costs in making the repairs and substitutions, but also by reason of the great loss in production through enforced idling of the machines.

My invention has for its chief aim to overcome the above mentioned drawbacks which objective is attained, as hereinafter more fully disclosed, through provision of a simple and reliable improved stop means which is applicable to existent straight knitting machines without requiring any structural changes in them or without interfering with their normal operation, and by which the machines are brought to an immediate standstill if the slur cam and yarn carrier drive bars should for any reason become un-timed.

In the drawings Fig. 1 is a skeletonized fragmentary view in front elevation of a straight stocking knitting machine with a safety stop mechanism conveniently embodying my invention.

Fig. 2 is a fragmentary view in top plan but drawn to a larger scale to illustrate the details of the stop mechanism more clearly.

Fig. 3 shows the mechanism in front elevation; and

Fig. 4 is a transverse sectional view taken as indicated by the arrows IV-IV in Fig. 3.

With more specific reference to these drawings, the usual longitudinally-extending bars from which the slur boxes and yarn carriers (not shown) derive their movements, are indicated at I and 6 respectively, and the fixed slur box guide bar and the friction rod at 5 and 8 respectively, the latter two being suitably supported by the machine framework comprehensively designated Correction of such and which are in turn respectively connected to said bars. The coulier mechanisms In and II are of the usual well known construction andv need not therefore be further described herein, .it being understood however that they are set up to induce synchronous reciprocatory movements in the bars 1 and 6 so that the slur cams and the yarn carriers of the machine are traversed back and forth in proper timed relation during the knitting.

The improvedautomatic mechanism which I have devised to automatically stop a straight knitting machine such as above briefly described in the event of differential movement between the bars I, 6 as a consequence of derangement or maloperation of either or both of the means It) and II, includes a fixedly-supported normallyclosed switch 20 which is interposed in circuit with an electric drive motor 2i (Fig. 3) whereby, through suitable intermediate transmission mechanism( not shown), the machine is arranged to be driven after common practice in the art. The operating arm 22 of the switch 20 is spring biased downwardly for maintenance in yielding engagement with a horizontal rod 23 supported between two arms 24 which are freely fulcrumed for pivotal movement about studs 25 at the distal ends of bracket arms 26 clamped to the friction shaft 8. As shown in Figs. 2 and 4, the switch 20 is supported by one of the bracket arms 26 whereto it is secured by screws 21. The rod 23, whereof the length is made somewhat in excess of the travel of the bars 6 and I, bears di-- rectly over top of an upright plunger 28 which is constrained to axial up and down movement in a bracket 29 secured by a screw bolt 30 to the friction bar 6. The beveled bottom shank end of the plunger 28 normally rests upon the flat bottom of a central notch 3| in a cam piece 32 fixedly secured to the slur cock connecting rod 1, said notch having complementally inclined cam slopes 3 5 a at opposite sides thereof.

From the foregoing it will be readily understood that if, in the event of failure or maloperation of either or both of the mechanisms l0, II or for any other reason the bars 6 and 7 should be moved differentially instead of synchronously in their traverse in either direction, the plunger 28 will be raised by encounter with one or the 3 other end slopes 31a of the notch 3| in cam piece 32. As a consequence, the bail-like trip ele- 'ment constituted by the rod 23 and its supporting arms 24 will be swung upward about the pivots 25 to actuate the lever 22 of the switch 20 for interruption of electric current flow to the driving motorof thef machine. I

I do-i10t of course consider-niyself -restricted to the precise details of construction herein disclosed by way of example, since, within the scope of the broader of the appended claims, variations may be made therein witnout'aepartmg from the spirit of the invention.

Having thus described -r'n'y invention, --I"claim:

1. Automatic safety stop n'i'echanism"-for--a' straight electric motor-driven knitting machine having two longitudinallyeextending *members, and separate means for reciprocating the members endwise in synchronism during the "knitting, said mechanism including a stationarily-mounted swi-tch connected -in *circuit" with the motor and having an actuatin'g arin; a 7 horizontal bail-like i trip e'lerrie'nt underlying the s'with act'uating ar-m, a -statioriary part of theinact-iineon which the trip len'ient is pivoted, an upright fplunger idirectl funderneath the trip element carried by ""onebf "the reciprocal-ted inenibers, and 'a cam notch inthether *recipro'cated' member' into which "the lower'end of the plunger normally exteiitis-whereby,"'inthe*event ofdifferential move- 'ment between the two membersftlre plunger is elevated to raise the itrip element for "actuation 4 of the switch arm and opening of the circuit to the motor.

2. Automatic safety stop mechanism for a straight electric motor-driven knitting machine having longitudinally-extending bars from which the slur cams and yarn carriers derive their movements,-and separate couli'ering cams and follower aarms for re'ciprocating the bars in synchronism during the knitting, said mechanism includin a stationarily-mounted switch connecting in circuit with..the .motor and having an actuating arm, a "horizontal bail l'ike trip element underlying the switch-actuating arm, a stationary part of the ma'chin'ezon which? the trip element is pivoted, an 5-i;pright{-pliinger directly underneath the trip *elein'nt, carried by one of the reciprocated bars, --and-a memberwith a cam notch on the other reciprocated rodinto which the lower end of the pl'unger normally extends, whereby in the event of differential movement between the two bars the plunger is elevated to raisesthe-trip :element riot-actuation of athe :switch rarm :andmpening-of thecircuit-to the'motor.

REFERENGES-CI'PED The {following .i fere'ncesare of record-an l the 'file 'of this patent:

UN'ITED STATES PATENTS Nulri-ber "Name Date 7 2,0151]. 06 Ga'StriCh .2. Sept; 24, 15 9 

